1. Technical Field
This invention relates to manufacturing multilayer printed wiring boards. The invention is more particularly related to a method for manufacturing multilayer printed wiring boards equipped with electronic elements including IC chips or other active elements, as well as chip capacitors or other passive elements.
2. Background Art
Integrated circuit (IC) chips are electrically connected with printed wiring boards by mounting methods including wire bonding, tape automated bonding (TAB), and flip-chip mounting. In addition, chip capacitors are often surface-mounted on substrates. IC chip mounting methods provide electrical connections via connection lead components (wires, leads, bumps) between the IC chip and the printed wiring board. These various lead components are prone to breakage and corrosion, which can cause interruption or malfunction of the electrical connection with the IC chip. Also, surface-mounting of chip capacitors increases the length of the wiring to the IC chip, which may cause undesirable electrical characteristics.
Accordingly, methods for manufacturing printed wiring boards containing an IC chip mounted on a package substrate by housing the IC chip in a concavity formed on the package substrate (e.g., core substrate, multi-layering inter-layer resin insulating layer and conduction circuit on the core substrate) has been disclosed in JP 2001-332863 and JP 2002-246757. The content of each of these publications is incorporated herein by reference. The arrangement of these publications is intended to improve connectivity between the printed wiring board and the IC chip.